Dynamo-electric machine



(No Model.)

B. A. SPBRRY. DYNAMO, ELECTRIC MACHINE.

Patented Dec. 28,1886.

7 EJJ'e J. [72 Van fol: 6/ i- UNITED STATES PATENT OFFICE.

ELMER A. SPERRY, OF CHICAGO, ILLINOIS.

DYNAMO-ELECTRIC MACHINE.

SPECIFICATION forming part of Letters Patent No. 354 9415, dated December 28, 1886.

Application filed October 31. 1884. Serial No. 146,947. (No model.) i

To all whom it may concern.-

Be it known that I, ELMER A. Srnauv, a citizen of the United States, residing at Ohicago, in the county of Cook and State of Illinois, have invented certain new and useful improvements in Field-Magnets for Dynamo- Electric Machines; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters and figures of reference marked thereon, which form a part of this specification.

The invention relates to a novel construction and arrangement of field-magnets for dynamo-electric machines; and it consists, first, in a peculiar construction of the pole-pieces forming the terminals of such magnets, and, secondly, it consists in a peculiar grouping of the pole-pieces about the armaturefacing them.

It has been found by continued experiment with dynamos in which an interior and exterior field pole-piece are used that where they are formed in one or more pieces and each piece magnetized by two or more helices having separate cores a given expenditure of energy in the helices, owing to the peculiar distribution of the magnetism in the pole-pieces, will not concentrate as much field upon the armature as when the pole-pieces are split up and each magnetized by a single helix and arranged with reference to one another in a peculiar manner. Ithas, furthermore, been discovered that a certain relation of the magnetic quantity of the pole-piece to the section of the core is necessary for maximum results, and it is the object of my invention to embody these discoveries in certain novel features of construction,as will be hereinafter more fully described, and specifically pointed out in the claims.

In the drawings, Figure 1 represents a side elevation of adynamo-machine embodying my invention; Fig. 2, a partial front elevation of the pole-pieces, showing the shaft and base of the machine in transverse section; and Fig. 3, a longitudinal section of one of the pole pieces and cores on line or a: of 2.

Similar letters ofreference indicate like parts cates the shaft of a dynamo loosely mounted at one end within a bearing, A, fixed upon an upright standard connected with the base of the machine, and at the other end within a bearing located in the yoke or back armatnre, 0.

Upon the armatnreshaft is mounted the driving-pulley D and the armature E, the outlines of which latter are indicated in dotted lines. This armature is mounted by a spider attached to one of the lateral edges, and is parallel to the field, as set forth in Letters Patent heretofore granted to me, and numbered 261,965, dated August 1, 1882. The coilsare connected with the commutator F in the usual manner, such commutator being controlled by the governor G, as is also described in previous Letters Patent, No. 268,956, dated December 12, 1882, granted tome.

From the commutatonbrushes H H thecurrent is led by wire 4 to the binding-post I, as indicated, and by wire 5 to the field-magnels, which are shown to be in a derived circuit. The yoke or back armature, O, is mounted upon a standard, 0, and from the face of the yoke project i'our cylindrical cores, two of which are represented in the symmetrical half-view shown in Fig. 2. Upon these cores are wound the usual coils constituting the field magnet helices of the machine, which may be in a derived circuit, as shown in the drawings, or in the work-ingcircuit. Integral with the outer ends of the cores, and forming terminals for the same, are two concentric sector-like projections, K K, forming pole'pieces which lie, respectively, interior and exterior to the armature.

By reference to Fig. 2 of the drawings it will be noticed .that the cores J are not placed equidistant in the circle, but are grouped in two pairs,the pole-pieces in each pair being brought in close proximity and so secured that the annular recess (indicated at L) between the seetorlike pole-picces (indicated at K K) will form a continuous annular groove or recess of a uniform radius. The relative position of the pole-pieces to the core can be traced in Figs. 2 and 3, and forms an important part of this invention, as does also the grouping of the pole-pieces circumferentially, as above described. This relation is as follows: The magnetic quantity of the pole-piece K is to that portion of the core which stands opposite and feeds it as that portion of the core which stands opposite and feeds the pole-piece K is to the magnetic quantity of the pole-piece K. In other words, if the larger portion of the core is represented by Y and the smaller by Z, the proportion isK YzzK Z. Itwillreadilybe understood that the groups of pole-pieces related as above to their cores may be grouped about the armature according to other ways than are shown in the drawings without departing'froin the spirit of the invention herein dcscribedthat is, the exterior sector-like pole-pieces, K, and the interior pole-pieces, K, forming the field of one-half of the armature, may be cast in one piece and supplied or cast with a core which will bear the relation to such semicircular polepieces above stated; or, furthermore, the pole-pieces may each represent less than a quadrant and be supplied with cores to which they bear the above relation, as will be readily understood.

Having thus fully described my invention, what I claim, and desire to secure by Letters Patent, is

1. Afield-niagnet for dynamoclectric machines, consisting of a core and concentric sector-like polepieces provided with an intervening circular groove to admitthe revolving end of an annular armature, as described, that portion of the sectional area of the core standing opposite each pole-piece being proportional to the sectional area or mass, respectively, of the pole-pieces themselves, substantially as and for the purpose set forth.

2. In a dynamoclectric machine, a fieldniagnet the poles of which are arranged in equidistantpairs or parts within a circle, each part or pair of the pole-pieces being magnetized by a separate and distinct core, and divided to admit the end of a revolving annular armature, the masses of the divisions of each pair or part being proportional, respectively, to the sectional area of the parts of the core opposite said divisions, substantially as described.

3. The combination of the back armature or yoke, O, the cores J, projecting from said yoke, the divided sector-like pole-pieces K K, bearing the specified relation to said cores J, and the annular armature E, playing between said pole-pieces, substantially as described.

In testimony whereofI aflix my signature in presence of two witnesses.

ELMER A. SPERRY.

Vitnesses:

CONSIDER H. \ViLLE'r'r, H. A. WooDBURY. 

